Type of Submission

Keywords

Abstract

In the fall of 2012, the CU Environmental Geology class did an assignment which produced a bathymetry (bottom-contour) map of Cedar Lake. Although the depth measurements using stadia rods and the position measurements using handheld GPS units were somewhat crude, the end result was a map that seemed to be a very reasonable depiction on the lake bottom configuration. In the fall 2014, measurements were again made as a part of an ongoing assessment to determine if sediment infill was occurring in the lake. The data gathering techniques duplicated those used in 2012, including equipment used. The primary difference between the two measurement events involved the number of depth readings taken, 364 readings were taken in 2014 and 138 were taken in 2012. Measurement locations and depths were determined by using Garmin GPS units and surveyors’ stadia rods. The data had to be processed using a variety of file types for the different software applications that were used. A Golden Software package called Surfer 8 was used to produce the bathymetry (bottom contour) maps of the lake and to calculate the water volume. The contour maps were then transferred into ArcGIS imagery for final presentation. The data collected in 2012 produced a volume of ~1,320,000 cubic feet and the data collected in 2014 produced a volume of ~1,450,000 cubic feet. This 130,000 cubic feet difference is an increase of almost a million gallons. This increase of water implies that there was not sediment infill but a sediment loss. Nearly 5 to 6 inches of additional water across the 6 acres of the lake surface would be required to produce this volume. During the past two years the lake has not been altered (dredged, for example) in any way to create a volume increase. This significant increase of water shows that the data collection method may have been too inaccurate to predict the sediment infill rate of the lake. Or, more likely, the increase in number of readings in 2014 has produced a more detailed bathymetry map than was produced in 2012. This, in turn, creates a volume discrepancy.

Downloads

Included in

Share

COinS

Apr 1st, 11:00 AMApr 1st, 2:00 PM

Progressive Assessment of Lake Depths in Cedar Lake

Cedarville, OH

In the fall of 2012, the CU Environmental Geology class did an assignment which produced a bathymetry (bottom-contour) map of Cedar Lake. Although the depth measurements using stadia rods and the position measurements using handheld GPS units were somewhat crude, the end result was a map that seemed to be a very reasonable depiction on the lake bottom configuration. In the fall 2014, measurements were again made as a part of an ongoing assessment to determine if sediment infill was occurring in the lake. The data gathering techniques duplicated those used in 2012, including equipment used. The primary difference between the two measurement events involved the number of depth readings taken, 364 readings were taken in 2014 and 138 were taken in 2012. Measurement locations and depths were determined by using Garmin GPS units and surveyors’ stadia rods. The data had to be processed using a variety of file types for the different software applications that were used. A Golden Software package called Surfer 8 was used to produce the bathymetry (bottom contour) maps of the lake and to calculate the water volume. The contour maps were then transferred into ArcGIS imagery for final presentation. The data collected in 2012 produced a volume of ~1,320,000 cubic feet and the data collected in 2014 produced a volume of ~1,450,000 cubic feet. This 130,000 cubic feet difference is an increase of almost a million gallons. This increase of water implies that there was not sediment infill but a sediment loss. Nearly 5 to 6 inches of additional water across the 6 acres of the lake surface would be required to produce this volume. During the past two years the lake has not been altered (dredged, for example) in any way to create a volume increase. This significant increase of water shows that the data collection method may have been too inaccurate to predict the sediment infill rate of the lake. Or, more likely, the increase in number of readings in 2014 has produced a more detailed bathymetry map than was produced in 2012. This, in turn, creates a volume discrepancy.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.